The present invention relates to a self-contained imaging assembly and, more particularly, to an improved self-contained imaging assembly in which a composition comprising photohardenable microcapsules and a developer material is disposed between a first transparent support and a second support which may be opaque or transparent to form a sealed assembly. The assembly is image-wise exposed to actinic radiation and subjected to an uniform rupturing force to provide an image in said composition which is visible against the second opaque support when viewed through the first transparent support or, if the second support is transparent, when the image is viewed as a transparency.
Photohardenable imaging systems employing microencapsulated radiation sensitive compositions are the subject of commonly assigned U.S. Pat. Nos. 4,399,209, 4,416,966 and 4,440,846. These imaging systems are characterized in that an imaging sheet including a layer of microcapsules containing a photohardenable composition in the internal phase is image-wise exposed to actinic radiation. In the most typical embodiments, the photohardenable composition is a photopolymerizable composition including a polyethylenically unsaturated compound and a photoinitiator and is encapsulated with a color former. Exposure to actinic radiation hardens the internal phase of the microcapsules. Following exposure, the imaging sheet is subjected to a uniform rupturing force by passing the sheet through the nip between a pair of pressure rollers.
Commonly assigned U.S. Pat. No. 4,440,846 discloses a self-contained imaging sheet in which the encapsulated color former and the developer material are co-deposited on one surface of a single substrate as one layer or as two contiguous layers. Upon image-wise exposing the imaging sheet and passing the sheet through pressure rollers, the microcapsules rupture and image-wise release the internal phase whereupon the color former migrates to the developer material where it reacts with the developer material and forms a colored image.
U.S. Pat. No. 4,766,050, commonly assigned, teaches an imaging system comprising a support, a layer containing microcapsules, a layer of developer material, and a layer containing an opacifying agent. The opacifying agent can form a separate layer or can be part of the layer containing the microcapsules or both but is interposed between the microcapsules and the developer to hide the microcapsules when viewing the image.